Riddle: What has keys but can't open locks, yet holds secrets…

Riddle

i-have-keys-but-open-no-locks-i-have-space-but-no-room-a60949

Riddle

i-can-be-cracked-made-told-and-played-yet-im-never

Riddle

i-speak-without-a-mouth-and-hear-without-ears-i-have-no-b993dc

Riddle

i-can-be-found-in-a-jar-but-not-in-a-can-i-have-many

Riddle

what-occurs-once-in-a-second-twice-in-a-moment-but